Indeed, comparison of haematoxylin-eosin (HE) and elastin stained aortas of 3-month old Fibulin-4+/+, Fibulin-4+/R and Fibulin-4R/R mice showed severe thickening and decellularization of the medial layer of the ascending aortic wall in Fibulin-4R/R mice and fragmented and disorganized elastin laminae resulting in 2–3 fold dilated ascending aortic aneurysms in all homozygous knockdown animals analyzed (Figure 2A). This evidence concerns the gene ELN and Ascending tubular aorta aneurysm.